Artificial stone



Patented June 25, 1929.

UNITED s'riiiasv PATENT oF'ricE.

ERNST I. MARS, 0F CHICAGO, ILLINOIS, ASSIGNOR TO TRIBIINE COMPANY, 0F CHICAGO,

ILLINOIS, A CORPORATION 0F ILLINOIS.

ARTIFICIAL STONE.

Application inea october i7, 1925'. sei-iai No. 63,179.

The present invention relates to the art op grinding and polishing stones and the li (e.

Among the objects of `the invention is to provide a novel grinding and polishing stone of line and homogeneous texture especially adapted for grinding and polishing surfaces of metal, such as etched cylinders of printving presses and the like. Heretofore, fine stones for this purpose, were quarriedbut the texture of the quarried Vstone varies in hardness, often being hard and soft in spots, and also are usually stratified with different ingredients and with different degrees of hardness. The present invention compreliends the idea of making the stone synthetically and with a homogeneous and uniform texture and vhardness so that t-lie eifectsof grinding and polishing will be unvaried and more efficient than is possible with natural stones.

The invention also comprehends the particular composition of the stones, aswell as the article itself and the method of making the same.

Other objects, advantages and capabilities i are compreliended by the invention as will later appear and are inherently possessed by the invention.

Referring to the'drawings illustrating a stone produced in accordance with-the invention, Figure 1 is a bottom plan view of such a stone, and Figure 2-is a view in elevationthereof.

In the illustrative embodiment of the invention, the stone is, in the specific case, made from the following ingredients in the proportions by weight of 80 parts of lead oxide or litharge, preferably in the powdered form,

40 parts of tripoli or tripoli powder, 8 parts of rotten stone, preferably in powdered form, 2 parts of brown sugar and 29 parts of glycerine, preferably white glycerine.

In theI process of producing this stone, the litharge, tripoli and rotten stone are preferably separately sifted through a suitable sieve, preferably of 300 mesh,` and then weighed out in the desired proportions and then mixed together dry.

The glycerine and brown sugar may be then mixed together by dissolving the sugar Y in the glycerine which is preferabrly of a specific gravity of about 1240 at Fahrenheit. This solution is then added to the dry mix` ture above mentioned and thoroughly mixed therewith. The mixing may be effected in a mixer wherein the substances may be thoroughly stirred and blended and forced through a screen or sieve to prevent or remove Alumps and spots.

of a flat hexagoii. The molded mass is then permitted to air dry in the mold for a suitable' length of time, such as two hours, and then taken froml the mold and permitted to `further dry in the air for a few more hours, such as from six to eight hours. The stone is then in condition to be put into use.

Such a stone is shown in Ithe drawings and is of hexagon shape and having a working surface 1, sides 2 and back 3, the sides and working surface meeting in rounded corners or beading or edges 4, and a shoulder 5 which is of Vaid in initiating the grinding and polishing action. In the center of the stone may also be provided an aperture 6 for permitting of the working of the worn away particles of the stone during the grinding operation, suoli particles being capable of working toward the aperture 6 where they may be released, and also toward the edges or shoulders 5 where they are also relieved at the slied and at the same time edect a relative rotatory` and oscillatory motion. When grinding, water is genera ly used so that the cutting or polishing action may be more efficient, and the particles breaking away from the stone will work their way toward the aperture 6 orthe edge of the stone. By making the stone non-circular aids in that the holder may positively rotate the stone and avoid any slippage that might occur if the stone were circular.

While I have herein described a particular composition and process of making the stone and a particular structure of the stone, as well as' shown the latter upon the drawing, it is to be understood that the invention is not limited thereto but also compreliends other compositions, methods of producing and other constructions, without departing from the spirit of the invention.

5 with litliarge and glycerine.

42. A composition for grinding-and polishing,comprising litharge, rotten stone and glycerin 3. A composition 'for grinding stance with lithnrge, rrotten stone und glyv cerine.,y

4. A composition orgrinding and polishing, comprising in the proportions by weight of eight parts of rotten stone,'foity arts of tripo ilv wder, twenty-nine parts o and eig ty parts of lithaigge.

find -polishf ing, comprising a-mixture of siliceous subg ycerine- 5. A composition for grinding and polishin comprising lit arge, tripoli powder, powdered rotten stone, brown su ar and white glycerine.

6. A composition for grindin and polishing, comprising a mixture of tripoli powder (consisting chiefly of silica), aldiluent substance,` and u binding agent, said mixture orming a vstone usable for grinding and polishing copper cylinders used in intaglio printing. v

7. A composition for grinding and polishing, comprising a mixture of litharge, tripoli, brown sugar, and glycerine.

In witness whereof, I hereunto subscribe my name to this specification.

ERNST P. MARS.

ii. mixture ofpowdered' 

